Partially self-erecting wind turbine tower
A partially self-erecting wind turbine tower and a method for carrying out the assembly thereof. A central telescoping pylon is provided. This is placed in an upright position, with its base on a temporary foundation. A plurality of legs is then attached to the telescoping pylon. The upper extreme of each of the plurality of legs is temporarily attached to the upper extreme of the telescoping pylon. With the pylon and legs thus secured, a nacelle is attached to the upper extreme of the telescoping pylon. A hub with attached blades is then affixed to the nacelle. The telescoping pylon is then forced upward through the collar to extend the height of the assembly.
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTNot Applicable
MICROFICHE APPENDIXNot Applicable
BACKGROUND OF THE INVENTION1. Field of the Invention
This invention relates to the field of wind energy production. More specifically the invention comprises a partially self-erecting wind turbine tower which significantly reduces the lift height required for assembly of the components.
2. Description of the Related Art
Nacelle 16 is attached to the top of pylon 14 via yaw joint 22. Drive mechanisms revolve the nacelle with respect to pylon 14 in order to point hub 18 into the wind.
The use of a single pylon in the prior art requires the diameter “D” of foundation 12 to be quite large. The mass of the foundation is required to counteract the large overturning forces placed on the base. The foundation is generally cast from concrete, and the use of such a large structure adds to the overall cost of the wind turbine installation.
The components of a prior art wind turbines are typically installed using a crane.
Prior art wind turbines are quite large. Blade lengths vary between 20 meters and 60 meters. The largest wind turbines have overall heights of about 200 meters with overall blade diameters of 125 meters. A very large wind turbine will have a pylon height of about 100 meters. Thus, a crane having a hook height of about 120 meters is needed to install the largest examples of prior art wind turbines. Such wind turbines are typically installed in remote locations, where access for large machinery is limited. Transporting extremely large cranes to such sites represents a substantial portion of the total cost of installing a wind turbine. Thus, a wind turbine tower design that could be erected using a smaller crane would be advantageous.
BRIEF SUMMARY OF THE INVENTIONThe present invention comprises a partially self-erecting wind turbine tower and a method for carrying out the assembly thereof. A central telescoping pylon is provided. This is placed in an upright position, with its base on a temporary foundation. A plurality of legs is then attached to the telescoping pylon. The upper extreme of each of the plurality of legs are preferably attached to a collar surrounding the upper extreme of the telescoping pylon.
With the pylon and legs thus temporarily secured, a nacelle is attached to the upper extreme of the telescoping pylon. A hub with attached blades is affixed to the nacelle. The telescoping pylon is then forced upward through the collar to extend the height of the assembly. The telescoping pylon is raised to its operational position with its lower extreme being affixed to the collar. By raising the telescoping pylon, the nacelle and attached hub and blades are positioned an appropriate distance above the ground.
The upper portion of each leg 36 is preferably attached to a collar 34, which surrounds telescoping pylon 32. The collar may formed by uniting portions of the legs themselves, or it may be a separate structure to which the legs are attached. Whatever form it takes, the collar provides a sliding attachment between the legs and telescoping pylon 32, so that the telescoping pylon can move up and down with respect to the legs.
The upper portions of the assembly shown are the same as those found in the prior art. Nacelle 16 is attached to the upper portion of the telescoping pylon by yaw joint 22. Hub 18 is attached to the nacelle. Blades 20 are attached to the hub.
The assembly of the components depicted in
The reader should understand that all the components are depicted in a “top level” fashion. As one example—pad 48 would typically include a number of through-holes to allow threaded studs embedded in the foundation to pass through the pad when it is placed in the proper position. Nuts would then be placed on these threaded shafts to lock the pad in places.
Likewise each collar sub-portion would typically include connecting flanges so that bolts or other devices can be used to secure each collar sub-portion to its neighbors. As these detailed components are well understood to those skilled in the art, they have been omitted in order to promote visual clarity.
One of the present invention's key advantages is the fact that the nacelle, hub, and blades can be attached before the pylon assembly is raised to its full height.
In
The reader will observe how the hook height above the ground is substantially reduced in comparison to the prior art process shown at
It is not necessary in the configuration shown in
Returning now to
Having received the information that the telescoping pylon is raised to its operational position after the nacelle is installed, the reader may wish to know some examples of the types of mechanisms that could be used to perform the raising. The present invention is in no way dependent upon the type of raising mechanism actually selected, so the following examples should properly be viewed as two examples among many other possibilities.
There are two basic approaches to raising the telescoping pylon. These shall be referred to as “internal” lifting mechanisms and “external” lifting mechanisms. In the internal approach, the lifting mechanism remains part of the tower assembly itself. In the external approach, the actual driving force for the lifting mechanism is external to the tower assembly. This latter approach is likely more cost-effective since once the tower is raised, it is likely to remain raised for extended periods. Thus, a single external lifting device could easily service several dozen wind turbine structures.
The advantage of this second approach is that the pulleys and cables are relatively inexpensive, and they are the only things which remain in the tower assembly. Thus, a single winch vehicle could service many different wind turbines.
A prestressing jack 68 is placed on an upper surface of the collar. Those skilled in the art will know that prestressing jacks are used to prestress cables in steel-reinforced concrete assemblies. They have a center passage through which the cable is passed. The cable is then secured to an extendable piston. In the embodiment of
As those skilled in the art will know, prestressing jacks can be configured to pull a cable for the length of a piston stroke, then reset the attachment between the piston and the cable at a lower position so that a new pull can be made. The cycle is then repeated for as many repetitions as are needed. Of course, other devices for holding the pylon in position while the jacks are reset can be employed.
Prestressing jacks could be used in an internal or external lifting configuration. They are relatively light and could be lifted into position as needed. Thus, a single set of jacks could serve many wind towers. Of course, they are also relatively inexpensive. Thus, in some applications, it would make sense to place a set of lifting jacks on each wind turbine.
Of course, the present invention provides operational options which simply were not present in the prior art. When high wind conditions are present in the prior art, the only option is to brake the spinning hub to a stop and feather the blades. Using the present invention, it is possible to lower the height of the nacelle to roughly half its operational height. If the leg design is modified to provide clearance this feature could make it possible to continue generating electricity even in high winds. Those skilled in the art will know that wind speed tapers significantly at lower altitude. The operational advantage of providing internal raising and lowering drives for the telescoping pylon—thereby providing relatively rapid movement of the telescoping pylon—may be sufficient in some circumstances to warrant the additional cost of such systems (though in many applications this may not be true).
Those skilled in the art will also realize that the ability to lower the height of the nacelle, hub, and blades will greatly facilitate maintenance operations. This is true regardless of whether the internal or external lifting approach is selected.
The number of legs selected for the assembly will depend upon many conditions and the invention is by no means limited to using only three legs.
The preceding description contains significant detail regarding the novel aspects of the present invention. It should not be construed, however, as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. As one example, the unitary structures depicted for the telescoping pylon and the legs could be made as multi-piece assemblies that are unified during the construction of the tower. Thus, the scope of the invention should be fixed by the following claims, rather than by the examples given.
Claims
1. A method of erecting a wind turbine tower and attaching it to the ground, comprising:
- a. providing a telescoping pylon, having a base and a top;
- b. providing a plurality of legs, wherein each of said plurality of legs has a lower extreme and an upper extreme;
- c. providing a nacelle;
- d. providing a hub;
- e. providing a plurality of blades;
- f. placing said base of said telescoping pylon on said ground and placing said telescoping pylon in a vertical orientation;
- g. placing said lower extreme of each of said plurality of legs on said ground and placing said upper extreme of each of said plurality of legs proximate said top of said telescoping pylon;
- h. providing a collar fixedly attached to said plurality of legs and slidably attached to said telescoping pylon;
- i. locking said collar in position with respect to said plurality of legs;
- j. attaching said plurality of blades to said hub;
- k. attaching said hub to said nacelle;
- l. forcing said telescoping pylon upward into a raised position where said base of said telescoping pylon lies proximate said collar; and
- m. fixing said telescoping pylon in said raised position.
2. A method of erecting a wind turbine tower as recited in claim 1, further comprising:
- a. providing a gear-driven drive system between said plurality of legs and said telescoping pylon; and
- b. engaging said gear-driven drive system to perform said step of forcing said telescoping pylon upward.
3. A method of erecting a wind turbine tower as recited in claim 1, further comprising:
- a. providing a cable anchor on said telescoping pylon;
- b. providing a cable affixed to said cable anchor; and
- c. applying tension to said cable in order to perform said step of forcing said telescoping pylon upward.
4. A method of erecting a wind turbine tower as recited in claim 3, further comprising using a lifting jack to apply said tension to said cable.
5. A method of erecting a wind turbine as recited in claim 1, wherein said telescoping pylon is comprised of at least two segments.
6. A method of erecting a wind turbine as recited in claim 1, wherein said collar is formed by uniting a plurality of collar sub-portions.
7. A method of erecting a wind turbine tower and attaching it to the ground, comprising:
- a. providing a telescoping pylon, having a base and a top;
- b. providing a plurality of legs, wherein each of said plurality of legs has a pad and a collar sub-portion;
- c. providing a nacelle;
- d. providing a hub;
- e. providing a plurality of blades;
- f. placing said base of said telescoping pylon on said ground and placing said telescoping pylon in a vertical orientation;
- g. placing said pad of each of said plurality of legs on said ground and placing said collar sub-portion of each of said plurality of legs proximate said top of said telescoping pylon;
- h. uniting said collar sub-portions to form a collar slidably attached to said telescoping pylon;
- i. attaching said plurality of blades to said hub;
- j. attaching said hub to said nacelle;
- k. forcing said telescoping pylon upward into a raised position where said base of said telescoping pylon lies proximate said collar; and
- l. fixing said telescoping pylon in said raised position.
8. A method of erecting a wind turbine tower as recited in claim 7, further comprising:
- a. providing a gear-driven drive system between said plurality of legs and said telescoping pylon; and
- b. engaging said gear-driven drive system to perform said step of forcing said telescoping pylon upward.
9. A method of erecting a wind turbine tower as recited in claim 7, further comprising:
- a. providing a cable anchor on said telescoping pylon;
- b. providing a cable affixed to said cable anchor; and
- c. applying tension to said cable in order to perform said step of forcing said telescoping pylon upward.
10. A method of erecting a wind turbine tower as recited in claim 9, further comprising using a lifting jack to apply said tension to said cable.
11. A method of erecting a wind turbine as recited in claim 7, wherein said telescoping pylon is comprised of at least two segments.
12. A method of erecting a wind turbine as recited in claim 7, wherein said collar sub-portions are integral to said legs.
13. A method of erecting a wind turbine tower and attaching it to the ground, comprising:
- a. providing a telescoping pylon, having a base and a top;
- b. providing a first leg, having a lower extreme and an upper extreme;
- c. providing a second leg having a lower extreme and an upper extreme;
- d. providing a third leg, having a lower extreme and an upper extreme;
- e. providing a nacelle;
- f. providing a hub;
- g. providing a plurality of blades;
- h. placing said base of said telescoping pylon on said ground and placing said telescoping pylon in a vertical orientation;
- i. placing said lower extreme of said first leg on said ground and placing said upper extreme of said first leg proximate said top of said telescoping pylon;
- j. placing said lower extreme of said second leg on said ground and placing said upper extreme of said second leg proximate said top of said telescoping pylon;
- k. placing said lower extreme of said third leg on said ground and placing said upper extreme of said third leg proximate said top of said telescoping pylon;
- l. attaching said plurality of blades to said hub;
- m. attaching said hub to said nacelle;
- n. forcing said telescoping pylon upward into a raised position where said base of said telescoping pylon lies proximate said upper extreme of each of said legs; and
- o. fixing said telescoping pylon in said raised position.
14. A method of erecting a wind turbine tower as recited in claim 13, further comprising:
- a. providing a gear-driven drive system between each of said legs and said telescoping pylon; and
- b. engaging said gear-driven drive system to perform said step of forcing said telescoping pylon upward.
15. A method of erecting a wind turbine tower as recited in claim 13, further comprising:
- a. providing a cable anchor on said telescoping pylon;
- b. providing a cable affixed to said cable anchor; and
- c. applying tension to said cable in order to perform said step of forcing said telescoping pylon upward.
16. A method of erecting a wind turbine tower as recited in claim 15, further comprising using a lifting jack to apply said tension to said cable.
17. A method of erecting a wind turbine as recited in claim 13, wherein said telescoping pylon is comprised of at least two segments.
18. A method of erecting a wind turbine as recited in claim 13, wherein said upper extremes of each of said legs form a collar surrounding said telescoping pylon.
19. A method of erecting a wind turbine as recited in claim 13 further comprising:
- a. providing a fourth leg having an upper extreme and a lower extreme; and
- b. placing said lower extreme of said fourth leg on said ground and placing said upper extreme of said fourth leg proximate said top of said telescoping pylon.
20. A method of erecting a wind turbine as recited in claim 19, wherein said upper extremes of each of said legs form a collar surrounding said telescoping pylon.
Type: Application
Filed: Feb 25, 2010
Publication Date: Dec 29, 2011
Patent Grant number: 8302365
Inventor: Anthony F. Gee (Tallahassee, FL)
Application Number: 12/660,371
International Classification: E04H 12/34 (20060101); E04H 12/00 (20060101);